The appendages of the epidermis

In the epidermis, structures such as stomata, trichomes, hydatodes and acumini differ.


Undoubtedly, stomata are the most important attachments related to the exchange of gases and water between the leaves and the environment.

Stomatic cells are the only cells in the epidermis that have chlorophyll. A stomata seen from above, resembles two beans arranged with the concavities facing each other: they are the two stomatal cells or guard cells, which have thicker cell wall on the concave face and whose arrangement leaves between them a space called stomatal slit or ostiole.

Beside each guard cell There is an annex, which has no chloroplasts - it is a common epidermal cell. In cross section, it is verified that the stomatal slit gives access to a space, the stomatal chamber, intercommunicating with the air spaces of the leaf filling parenchyma.

Attention! The exchange of gases between the plant and the environment occurs through the stomata of the epidermis and a structure called lenticels present in the sub.

Lentils are small openings that facilitate the ingress and egress of gases into the suberified roots and stems.


Trichomes are usually specialized structures against water loss due to excessive perspiration occurring in a hot climate plant. They can, however, be secretory, producing oily, digestive or hives secretions. Carnivorous plants have “digestive” trichomes and the nettle, a plant that causes skin irritation, has stinging trichomes.


Acuolees, pointed structures that protect the plant against predators, are often mistaken for thorns, which are modified leaves or branches. The oils are easy to detach and come from the epidermis. They can be found in rose bushes.


Hidatodes are modified stomata that specialize in eliminating excess liquid from the plant. The hydatodes usually present at the edges of the leaves, where, in the morning, it is possible to observe the drops of liquid that they eliminate, a phenomenon known as gutation.